They're your characters, love them or hate them. Personalize them. Let your reader know who they are and what they look like. Give them a charcteristic that is personal and defining. A scar, a way of wrinkling their nose when they smile. A habit that sets them aside from everyone else.
Does she flip her hair behind her ear or suck in her lower lip when she's nervous? Does he rake his fingers through his hair or rub the palm of his hand over his chin?
Maybe she wears her clothes too tight or skirt too short. He could leave the top three buttons of his shirt open. Even the smallest tic will define your character. Have fun with it and your readers will be drawn into your story and will identify with them.
Look for my latest book, "Olivia," at the end of August at Snowy Creek Books.